Slip-dominated deformation mechanisms and tensile anisotropy of rolled Mg-6.3Gd-3Li-2Zn-0.5Al alloy based on crystal plasticity analysis

Abstract

In this work, mechanical properties, the tensile anisotropy, and deformation mechanisms during tensile testing of rolled Mg-6.3Gd-3Li-2Zn-0.5Al alloys (R2 and R4) were analyzed with Visco-Plastic Self-Consistent (VPSC) model and material characterization techniques. The results showed that the mechanical properties of the rolled Mg-Gd-Li alloy displayed considerable anisotropy, with highest yield strength and tensile strength along the rolling direction (RD) measured at 272.3 MPa and 294.5 MPa, respectively. Conversely, the yield and tensile strength in the transverse direction (TD) were merely 214.7 MPa and 253.1 MPa, respectively. Furthermore, the anisotropy increased with the deformation. The VPSC models for rolled Mg-Gd-Li alloy in tensile deformation were constructed, respectively, by adjusting the hardening parameters. Pyramidal <c + a> slip, which dominated the deformation mechanisms of Mg-Gd-Li alloy, was calculated via VPSC model and observed in electron backscatter diffraction (EBSD) data. The stress-strain curves and pole figures generated from the VPSC model exhibited excellent agreement with experimental results. For the rolled Mg-Gd-Li alloy, the activation levels of basal <a> slip along different tensile directions were the main cause of the anisotropy in yield strength. On the other hand, the activation levels of (10–12) twinning during deformation in various tensile orientations were primarily responsible for the anisotropy in tensile strength.